OR LIFE-HISTOEX OF CERTAIN ACAEINA. 373 



they were parasitic ; he observed the absence of maudibles, and, 

 as he considered, of any mouth whatever, and of any reproductive 

 organs or anus. He observed that some Sypopi, immediately 

 before the ecdysis, contained within their skin, and completely 

 filling it, an Acarus different from themselves, and possessed of 

 chelate mandibles and paljDi ; finding them in company with 

 Gamasids, and in places where Gamasids were found, he came to 

 the conclusion that Hypopus was a young form of G-amasus. 



Fiirsteuberg, in L861*, in his work on the Sarcoptidse of Mam- 

 mals, figures and describes an Acarid, which he considered as 

 belonging to Koch's genus Homopus, and which Gwilt had found 

 in immense numbers on the skin of a recently-stuffed elephant, 

 for which, not very sufBcient, reason he calls it Homopus elephantis. 

 It is not quite clear why Fiirsteuberg deals with it at all, as he ex- 

 pressly says that, although a parasite, it is not an Itch-mite ; pro- 

 bably it was because Gerlach held a different opinion and called 

 it " Symbiotes elephantis;'''' but, having dealt with it, Fiirstenberg 

 gave a very different description of its mouth-organs from what 

 other writers had given for Hypopus ; he described maxillae 

 divided into two equal parts and placed between three-jointed 

 palpi. Fiirstenberg carried his measurements to the 4th place 

 of decimals of a millimeter. 



Claparedet was the next contributor to the literature o'^ Hypo- 

 pus, in the year 1868 ; he may certainly have the credit of first 

 connecting Hypopus in an intelligent manner with Tyroglypihus, 

 although Gervais had classed them together. Claparede found, 

 on liyacinth-bulbs, &c., what he considered to be a new species 

 of Tyroglyphus. He had it in great profusion, kept up his obser- 

 vations for three years, and bred large numbers of the creatures, 

 which he called Tyroglyphus Dujardinii; but he never found a 

 male, all the specimens he noticed were females. He did not find 

 any Gamasids, but he did find great quantities of Hypopi, and 

 moreover he actually saw some nymphs of Tyroglyphus, which 

 closely resemble the adult, cast the skin and produce, not a per- 

 fect Tyroglyphus, as the other nymphs of the same species did, 

 but a Hypopus. He never could see any eggs in a Hypopus. 

 Claparede's observations were absolutely correct, but the de- 

 duction which he drew from them was that Hypopus was the male 

 of Tyroglyphus. Claparede took the opportunity of attacking 



* 'Die Kratzmilben von Mensctien unci Tliieren' (Leipzig, 1861), p. 208. 

 t " Studien an Acariden," Zeitschr. wiss. Zool. 18 Band, p. 445. 



